MPEP § 2138.04 — “Conception” (Annotated Rules)

§2138.04 “Conception”

USPTO MPEP version: BlueIron's Update: 2026-01-10

This page consolidates and annotates all enforceable requirements under MPEP § 2138.04, including statutory authority, regulatory rules, examiner guidance, and practice notes. It is provided as guidance, with links to the ground truth sources. This is information only, it is not legal advice.

“Conception”

This section addresses “Conception”. Primary authority: 35 U.S.C. 100, 35 U.S.C. 102, and 35 U.S.C. 102(g). Contains: 3 requirements, 2 prohibitions, and 7 other statements.

Key Rules

Topic

PTAB Contested Case Procedures

4 rules
StatutoryInformativeAlways
[mpep-2138-04-450d4d103ada4883c4c8f610]
Invention Formation Requirement
Note:
The inventor must have a definite and permanent idea of the complete invention as it is to be applied in practice without extensive experimentation.

Conception has been defined as “the complete performance of the mental part of the inventive act” and it is “the formation in the mind of the inventor of a definite and permanent idea of the complete and operative invention as it is thereafter to be applied in practice….” Townsend v. Smith, 36 F.2d 292, 295, 4 USPQ 269, 271 (CCPA 1929). “[C]onception is established when the invention is made sufficiently clear to enable one skilled in the art to reduce it to practice without the exercise of extensive experimentation or the exercise of inventive skill.” Hiatt v. Ziegler, 179 USPQ 757, 763 (Bd. Pat. Inter. 1973). Conception has also been defined as a disclosure of an invention which enables one skilled in the art to reduce the invention to a practical form without “exercise of the inventive faculty.” Gunter v. Stream, 573 F.2d 77, 197 USPQ 482 (CCPA 1978). See also Coleman v. Dines, 754 F.2d 353, 224 USPQ 857 (Fed. Cir. 1985) (It is settled that in establishing conception a party must show possession of every feature recited in the count, and that every limitation of the count must have been known to the inventor at the time of the alleged conception. Conception must be proved by corroborating evidence.); Hybritech Inc. v. Monoclonal Antibodies Inc., 802 F. 2d 1367, 1376, 231 USPQ 81, 87 (Fed. Cir. 1986) (Conception is the “formation in the mind of the inventor, of a definite and permanent idea of the complete and operative invention, as it is hereafter to be applied in practice.”); Hitzeman v. Rutter, 243 F.3d 1345, 58 USPQ2d 1161 (Fed. Cir. 2001) (Inventor’s “hope” that a genetically altered yeast would produce antigen particles having the particle size and sedimentation rates recited in the claims did not establish conception, since the inventor did not show that he had a “definite and permanent understanding” as to whether or how, or a reasonable expectation that, the yeast would produce the recited antigen particles.); Staehelin v. Secher, 24 USPQ2d 1513, 1522 (Bd. Pat. App. & Inter. 1992) (“evidence of conception naming only one of the actual inventive entity inures to the benefit of and serves as evidence of conception by the complete inventive entity”).

Jump to MPEP SourcePTAB Contested Case Procedures
StatutoryInformativeAlways
[mpep-2138-04-672f336b8a110118a309692c]
Invention Must Be Clearly Conceived Without Extensive Experimentation
Note:
The invention must be clearly conceived in the mind of the inventor so that a skilled artisan can reduce it to practice without extensive experimentation or inventive skill.

Conception has been defined as “the complete performance of the mental part of the inventive act” and it is “the formation in the mind of the inventor of a definite and permanent idea of the complete and operative invention as it is thereafter to be applied in practice….” Townsend v. Smith, 36 F.2d 292, 295, 4 USPQ 269, 271 (CCPA 1929). “[C]onception is established when the invention is made sufficiently clear to enable one skilled in the art to reduce it to practice without the exercise of extensive experimentation or the exercise of inventive skill.” Hiatt v. Ziegler, 179 USPQ 757, 763 (Bd. Pat. Inter. 1973). Conception has also been defined as a disclosure of an invention which enables one skilled in the art to reduce the invention to a practical form without “exercise of the inventive faculty.” Gunter v. Stream, 573 F.2d 77, 197 USPQ 482 (CCPA 1978). See also Coleman v. Dines, 754 F.2d 353, 224 USPQ 857 (Fed. Cir. 1985) (It is settled that in establishing conception a party must show possession of every feature recited in the count, and that every limitation of the count must have been known to the inventor at the time of the alleged conception. Conception must be proved by corroborating evidence.); Hybritech Inc. v. Monoclonal Antibodies Inc., 802 F. 2d 1367, 1376, 231 USPQ 81, 87 (Fed. Cir. 1986) (Conception is the “formation in the mind of the inventor, of a definite and permanent idea of the complete and operative invention, as it is hereafter to be applied in practice.”); Hitzeman v. Rutter, 243 F.3d 1345, 58 USPQ2d 1161 (Fed. Cir. 2001) (Inventor’s “hope” that a genetically altered yeast would produce antigen particles having the particle size and sedimentation rates recited in the claims did not establish conception, since the inventor did not show that he had a “definite and permanent understanding” as to whether or how, or a reasonable expectation that, the yeast would produce the recited antigen particles.); Staehelin v. Secher, 24 USPQ2d 1513, 1522 (Bd. Pat. App. & Inter. 1992) (“evidence of conception naming only one of the actual inventive entity inures to the benefit of and serves as evidence of conception by the complete inventive entity”).

Jump to MPEP SourcePTAB Contested Case Procedures
StatutoryRequiredAlways
[mpep-2138-04-4128849f9263ed6bce2fac89]
Invention Must Be Fully Conceived Without Inventive Skill
Note:
The inventor must have a definite and permanent idea of the complete invention, enabling one skilled in the art to reduce it to practice without extensive experimentation.

Conception has been defined as “the complete performance of the mental part of the inventive act” and it is “the formation in the mind of the inventor of a definite and permanent idea of the complete and operative invention as it is thereafter to be applied in practice….” Townsend v. Smith, 36 F.2d 292, 295, 4 USPQ 269, 271 (CCPA 1929). “[C]onception is established when the invention is made sufficiently clear to enable one skilled in the art to reduce it to practice without the exercise of extensive experimentation or the exercise of inventive skill.” Hiatt v. Ziegler, 179 USPQ 757, 763 (Bd. Pat. Inter. 1973). Conception has also been defined as a disclosure of an invention which enables one skilled in the art to reduce the invention to a practical form without “exercise of the inventive faculty.” Gunter v. Stream, 573 F.2d 77, 197 USPQ 482 (CCPA 1978). See also Coleman v. Dines, 754 F.2d 353, 224 USPQ 857 (Fed. Cir. 1985) (It is settled that in establishing conception a party must show possession of every feature recited in the count, and that every limitation of the count must have been known to the inventor at the time of the alleged conception. Conception must be proved by corroborating evidence.); Hybritech Inc. v. Monoclonal Antibodies Inc., 802 F. 2d 1367, 1376, 231 USPQ 81, 87 (Fed. Cir. 1986) (Conception is the “formation in the mind of the inventor, of a definite and permanent idea of the complete and operative invention, as it is hereafter to be applied in practice.”); Hitzeman v. Rutter, 243 F.3d 1345, 58 USPQ2d 1161 (Fed. Cir. 2001) (Inventor’s “hope” that a genetically altered yeast would produce antigen particles having the particle size and sedimentation rates recited in the claims did not establish conception, since the inventor did not show that he had a “definite and permanent understanding” as to whether or how, or a reasonable expectation that, the yeast would produce the recited antigen particles.); Staehelin v. Secher, 24 USPQ2d 1513, 1522 (Bd. Pat. App. & Inter. 1992) (“evidence of conception naming only one of the actual inventive entity inures to the benefit of and serves as evidence of conception by the complete inventive entity”).

Jump to MPEP SourcePTAB Contested Case Procedures
StatutoryRequiredAlways
[mpep-2138-04-30e57f99477f689a9c0e456c]
Conception Must Be Proved by Corroborating Evidence
Note:
The inventor must demonstrate a definite and permanent idea of the complete invention, supported by evidence.

Conception has been defined as “the complete performance of the mental part of the inventive act” and it is “the formation in the mind of the inventor of a definite and permanent idea of the complete and operative invention as it is thereafter to be applied in practice….” Townsend v. Smith, 36 F.2d 292, 295, 4 USPQ 269, 271 (CCPA 1929). “[C]onception is established when the invention is made sufficiently clear to enable one skilled in the art to reduce it to practice without the exercise of extensive experimentation or the exercise of inventive skill.” Hiatt v. Ziegler, 179 USPQ 757, 763 (Bd. Pat. Inter. 1973). Conception has also been defined as a disclosure of an invention which enables one skilled in the art to reduce the invention to a practical form without “exercise of the inventive faculty.” Gunter v. Stream, 573 F.2d 77, 197 USPQ 482 (CCPA 1978). See also Coleman v. Dines, 754 F.2d 353, 224 USPQ 857 (Fed. Cir. 1985) (It is settled that in establishing conception a party must show possession of every feature recited in the count, and that every limitation of the count must have been known to the inventor at the time of the alleged conception. Conception must be proved by corroborating evidence.); Hybritech Inc. v. Monoclonal Antibodies Inc., 802 F. 2d 1367, 1376, 231 USPQ 81, 87 (Fed. Cir. 1986) (Conception is the “formation in the mind of the inventor, of a definite and permanent idea of the complete and operative invention, as it is hereafter to be applied in practice.”); Hitzeman v. Rutter, 243 F.3d 1345, 58 USPQ2d 1161 (Fed. Cir. 2001) (Inventor’s “hope” that a genetically altered yeast would produce antigen particles having the particle size and sedimentation rates recited in the claims did not establish conception, since the inventor did not show that he had a “definite and permanent understanding” as to whether or how, or a reasonable expectation that, the yeast would produce the recited antigen particles.); Staehelin v. Secher, 24 USPQ2d 1513, 1522 (Bd. Pat. App. & Inter. 1992) (“evidence of conception naming only one of the actual inventive entity inures to the benefit of and serves as evidence of conception by the complete inventive entity”).

Jump to MPEP SourcePTAB Contested Case Procedures
Topic

Process (Method)

3 rules
StatutoryInformativeAlways
[mpep-2138-04-3c634e474248ef09903bc82e]
Conception of Species Does Not Imply Conception of Genus
Note:
The conception of a specific species within a genus does not necessarily imply the conception of the entire genus or other species within it.

The first to conceive of a species is not necessarily the first to conceive of the generic invention. In re Jolley, 308 F.3d 1317, 1323 n.2, 64 USPQ2d 1901, 1905 n.2 (Fed. Cir. 2002). Further, while conception of a species within a genus may constitute conception of the genus, conception of one species and the genus may not constitute conception of another species in the genus. Oka v. Youssefyeh, 849 F.2d 581, 7 USPQ2d 1169 (Fed. Cir. 1988) (conception of a chemical requires both the idea of the structure of the chemical and possession of an operative method of making it). See also Amgen, Inc. v. Chugai Pharmaceutical Co., 927 F.2d 1200, 1206, 18 USPQ2d 1016, 1021 (Fed. Cir. 1991) (in the isolation of a gene, defining a gene by its principal biological property is not sufficient for conception absent an ability to envision the detailed constitution as well as a method for obtaining it); Fiers v. Revel, 984 F.2d 1164, 1170, 25 USPQ2d 1601, 1605 (Fed. Cir. 1993) (“[b]efore reduction to practice, conception only of a process for making a substance, without conception of a structural or equivalent definition of that substance, can at most constitute a conception of the substance claimed as a process” but cannot constitute conception of the substance; as “conception is not enablement,” conception of a purified DNA sequence coding for a specific protein by function and a method for its isolation that could be carried out by one of ordinary skill in the art is not conception of that material). See MPEP §§ 2106.04(b) and 2106.04(c) for information on the subject matter eligibility of inventions involving isolated genes.

Jump to MPEP SourceProcess (Method)Statutory Categories of InventionSequence Listing Format
StatutoryProhibitedAlways
[mpep-2138-04-8297eda7677999440b3c470e]
Conception of One Species Does Not Constitute Another
Note:
The conception of one species within a genus does not equate to the conception of another species in the same genus.

The first to conceive of a species is not necessarily the first to conceive of the generic invention. In re Jolley, 308 F.3d 1317, 1323 n.2, 64 USPQ2d 1901, 1905 n.2 (Fed. Cir. 2002). Further, while conception of a species within a genus may constitute conception of the genus, conception of one species and the genus may not constitute conception of another species in the genus. Oka v. Youssefyeh, 849 F.2d 581, 7 USPQ2d 1169 (Fed. Cir. 1988) (conception of a chemical requires both the idea of the structure of the chemical and possession of an operative method of making it). See also Amgen, Inc. v. Chugai Pharmaceutical Co., 927 F.2d 1200, 1206, 18 USPQ2d 1016, 1021 (Fed. Cir. 1991) (in the isolation of a gene, defining a gene by its principal biological property is not sufficient for conception absent an ability to envision the detailed constitution as well as a method for obtaining it); Fiers v. Revel, 984 F.2d 1164, 1170, 25 USPQ2d 1601, 1605 (Fed. Cir. 1993) (“[b]efore reduction to practice, conception only of a process for making a substance, without conception of a structural or equivalent definition of that substance, can at most constitute a conception of the substance claimed as a process” but cannot constitute conception of the substance; as “conception is not enablement,” conception of a purified DNA sequence coding for a specific protein by function and a method for its isolation that could be carried out by one of ordinary skill in the art is not conception of that material). See MPEP §§ 2106.04(b) and 2106.04(c) for information on the subject matter eligibility of inventions involving isolated genes.

Jump to MPEP SourceProcess (Method)Statutory Categories of InventionSequence Listing Format
StatutoryProhibitedAlways
[mpep-2138-04-c70b1dae93c2e106a7e51f08]
Conception Requires Structure and Method
Note:
Inventors must conceive both the chemical structure and a method for making it to claim an invention.

The first to conceive of a species is not necessarily the first to conceive of the generic invention. In re Jolley, 308 F.3d 1317, 1323 n.2, 64 USPQ2d 1901, 1905 n.2 (Fed. Cir. 2002). Further, while conception of a species within a genus may constitute conception of the genus, conception of one species and the genus may not constitute conception of another species in the genus. Oka v. Youssefyeh, 849 F.2d 581, 7 USPQ2d 1169 (Fed. Cir. 1988) (conception of a chemical requires both the idea of the structure of the chemical and possession of an operative method of making it). See also Amgen, Inc. v. Chugai Pharmaceutical Co., 927 F.2d 1200, 1206, 18 USPQ2d 1016, 1021 (Fed. Cir. 1991) (in the isolation of a gene, defining a gene by its principal biological property is not sufficient for conception absent an ability to envision the detailed constitution as well as a method for obtaining it); Fiers v. Revel, 984 F.2d 1164, 1170, 25 USPQ2d 1601, 1605 (Fed. Cir. 1993) (“[b]efore reduction to practice, conception only of a process for making a substance, without conception of a structural or equivalent definition of that substance, can at most constitute a conception of the substance claimed as a process” but cannot constitute conception of the substance; as “conception is not enablement,” conception of a purified DNA sequence coding for a specific protein by function and a method for its isolation that could be carried out by one of ordinary skill in the art is not conception of that material). See MPEP §§ 2106.04(b) and 2106.04(c) for information on the subject matter eligibility of inventions involving isolated genes.

Jump to MPEP SourceProcess (Method)Statutory Categories of InventionSequence Listing Format
Topic

Inventor of Discovered Plant

3 rules
StatutoryInformativeAlways
[mpep-2138-04-3669101298833744b5199c72]
Conception and Reduction to Practice Occur Simultaneously in Unpredictable Technologies
Note:
In unpredictable areas of chemistry and biology, conception is not complete until the invention has been reduced to practice.

On rare occasions conception and reduction to practice occur simultaneously in unpredictable technologies. Alpert v. Slatin, 305 F.2d 891, 894, 134 USPQ 296, 299 (CCPA 1962). “[I]n some unpredictable areas of chemistry and biology, there is no conception until the invention has been reduced to practice.” MacMillan v. Moffett, 432 F.2d 1237, 1234-40, 167 USPQ 550, 552-553 (CCPA 1970). See also Hitzeman v. Rutter, 243 F.3d 1345, 58 USPQ2d 1161 (Fed. Cir. 2001) (conception simultaneous with reduction to practice where appellant lacked reasonable certainty that yeast’s performance of certain intracellular processes would result in the claimed antigen particles); Dunn v. Ragin, 50 USPQ 472, 475 (Bd. Pat. Inter. 1941) (a new variety of asexually reproduced plant is conceived and reduced to practice when it is grown and recognized as a new variety). Under these circumstances, conception is not complete if subsequent experimentation reveals factual uncertainty which “so undermines the specificity of the inventor’s idea that it is not yet a definite and permanent reflection of the complete invention as it will be used in practice.” Burroughs Wellcome Co. v. Barr Labs., Inc., 40 F.3d 1223, 1229, 32 USPQ2d 1915, 1920 (Fed. Cir. 1994).

Jump to MPEP SourceInventor of Discovered PlantPlant Patent Inventor and OathPlant Patent Practice
StatutoryInformativeAlways
[mpep-2138-04-782caa766cbb00c92fb9e345]
Conception Not Complete If Subsequent Experiments Uncertain
Note:
Conception is not complete if subsequent experiments reveal factual uncertainty that undermines the inventor’s specific idea of the invention.

On rare occasions conception and reduction to practice occur simultaneously in unpredictable technologies. Alpert v. Slatin, 305 F.2d 891, 894, 134 USPQ 296, 299 (CCPA 1962). “[I]n some unpredictable areas of chemistry and biology, there is no conception until the invention has been reduced to practice.” MacMillan v. Moffett, 432 F.2d 1237, 1234-40, 167 USPQ 550, 552-553 (CCPA 1970). See also Hitzeman v. Rutter, 243 F.3d 1345, 58 USPQ2d 1161 (Fed. Cir. 2001) (conception simultaneous with reduction to practice where appellant lacked reasonable certainty that yeast’s performance of certain intracellular processes would result in the claimed antigen particles); Dunn v. Ragin, 50 USPQ 472, 475 (Bd. Pat. Inter. 1941) (a new variety of asexually reproduced plant is conceived and reduced to practice when it is grown and recognized as a new variety). Under these circumstances, conception is not complete if subsequent experimentation reveals factual uncertainty which “so undermines the specificity of the inventor’s idea that it is not yet a definite and permanent reflection of the complete invention as it will be used in practice.” Burroughs Wellcome Co. v. Barr Labs., Inc., 40 F.3d 1223, 1229, 32 USPQ2d 1915, 1920 (Fed. Cir. 1994).

Jump to MPEP SourceInventor of Discovered PlantPlant Patent Inventor and OathPlant Patent Practice
StatutoryInformativeAlways
[mpep-2138-04-14aa7e5180436e103b500ea1]
Conception Is Not Complete Without Specificity
Note:
The rule states that conception is not complete if subsequent experimentation reveals factual uncertainty, undermining the specificity of the inventor's idea.

On rare occasions conception and reduction to practice occur simultaneously in unpredictable technologies. Alpert v. Slatin, 305 F.2d 891, 894, 134 USPQ 296, 299 (CCPA 1962). “[I]n some unpredictable areas of chemistry and biology, there is no conception until the invention has been reduced to practice.” MacMillan v. Moffett, 432 F.2d 1237, 1234-40, 167 USPQ 550, 552-553 (CCPA 1970). See also Hitzeman v. Rutter, 243 F.3d 1345, 58 USPQ2d 1161 (Fed. Cir. 2001) (conception simultaneous with reduction to practice where appellant lacked reasonable certainty that yeast’s performance of certain intracellular processes would result in the claimed antigen particles); Dunn v. Ragin, 50 USPQ 472, 475 (Bd. Pat. Inter. 1941) (a new variety of asexually reproduced plant is conceived and reduced to practice when it is grown and recognized as a new variety). Under these circumstances, conception is not complete if subsequent experimentation reveals factual uncertainty which “so undermines the specificity of the inventor’s idea that it is not yet a definite and permanent reflection of the complete invention as it will be used in practice.” Burroughs Wellcome Co. v. Barr Labs., Inc., 40 F.3d 1223, 1229, 32 USPQ2d 1915, 1920 (Fed. Cir. 1994).

Jump to MPEP SourceInventor of Discovered PlantPlant Patent Inventor and OathPlant Patent Practice
Topic

Testimony Request Procedures

2 rules
StatutoryRequiredAlways
[mpep-2138-04-494504f52126b02b734ab96b]
Inventor Must Form Definite Idea of Complete Invention
Note:
The inventor must have a clear and permanent understanding of the complete and operable invention to establish conception. Testimony from non-inventors is insufficient to establish the meaning of variables in an inventor’s notebook.

The inventor must form a definite and permanent idea of the complete and operable invention to establish conception. Bosies v. Benedict, 27 F.3d 539, 543, 30 USPQ2d 1862, 1865 (Fed. Cir. 1994) (Testimony by a noninventor as to the meaning of a variable of a generic compound described in an inventor’s notebook was insufficient as a matter of law to establish the meaning of the variable because the testimony was not probative of what the inventor conceived.). A person who shares in the conception of a claimed invention is a joint inventor of that invention. In re VerHoef, 888 F.3d 1362, 1366-67, 126 F.2d 1561, 1564-65 (Fed. Cir. 2018).

Jump to MPEP SourceTestimony Request ProceduresUSPTO Employee Testimony
StatutoryInformativeAlways
[mpep-2138-04-1ac227c626462cfd66e75bee]
Person Sharing Conception Is Joint Inventor
Note:
A person who contributes to the conception of an invention is considered a joint inventor.

The inventor must form a definite and permanent idea of the complete and operable invention to establish conception. Bosies v. Benedict, 27 F.3d 539, 543, 30 USPQ2d 1862, 1865 (Fed. Cir. 1994) (Testimony by a noninventor as to the meaning of a variable of a generic compound described in an inventor’s notebook was insufficient as a matter of law to establish the meaning of the variable because the testimony was not probative of what the inventor conceived.). A person who shares in the conception of a claimed invention is a joint inventor of that invention. In re VerHoef, 888 F.3d 1362, 1366-67, 126 F.2d 1561, 1564-65 (Fed. Cir. 2018).

Jump to MPEP SourceTestimony Request ProceduresUSPTO Employee Testimony
Topic

Key Changes Under AIA

1 rules
StatutoryInformativeAlways
[mpep-2138-04-dad9db7012bfe9f06adc6849]
Key Changes Under AIA for Pre-Post Filing Claims
Note:
This rule outlines the key changes under the America Invents Act (AIA) for patents with claims having both pre-AIA and post-AIA effective filing dates.

[Editor Note: This MPEP section has limited applicability to applications subject to examination under the first inventor to file (FITF) provisions of the AIA as set forth in 35 U.S.C. 100 (note). Patents and applications that contain (or contained at any time) at least one claim with a pre-AIA effective filing date (before March 16, 2013) and at least one claim with a post-AIA effective filing date (on or after March 16, 2013) are subject to the patentability requirements in AIA 35 U.S.C. 102 – 103 and subject to pre-AIA 35 U.S.C. 102(g).See MPEP § 2159 et seq.]

Jump to MPEP SourceKey Changes Under AIAAIA vs Pre-AIA PracticeConception and Reduction to Practice
Topic

AIA Effective Dates

1 rules
StatutoryInformativeAlways
[mpep-2138-04-6b48940f7ac9b0d1baf155c4]
Patents with Mixed AIA and Pre-AIA Claims Subject to Both Laws
Note:
Patents containing claims from both pre-AIA and post-AIA filing dates must comply with both AIA and pre-AIA patentability requirements.

[Editor Note: This MPEP section has limited applicability to applications subject to examination under the first inventor to file (FITF) provisions of the AIA as set forth in 35 U.S.C. 100 (note). Patents and applications that contain (or contained at any time) at least one claim with a pre-AIA effective filing date (before March 16, 2013) and at least one claim with a post-AIA effective filing date (on or after March 16, 2013) are subject to the patentability requirements in AIA 35 U.S.C. 102 – 103 and subject to pre-AIA 35 U.S.C. 102(g).See MPEP § 2159 et seq.]

Jump to MPEP SourceAIA Effective DatesDetermining Whether Application Is AIA or Pre-AIAAIA Overview and Effective Dates
Topic

Plant Patent Practice

1 rules
StatutoryInformativeAlways
[mpep-2138-04-c034b94508dba6bb2450f381]
Conception and Reduction to Practice Occur Simultaneously in Unpredictable Technologies
Note:
In some unpredictable areas of chemistry and biology, conception is not complete until the invention has been reduced to practice due to factual uncertainties.

On rare occasions conception and reduction to practice occur simultaneously in unpredictable technologies. Alpert v. Slatin, 305 F.2d 891, 894, 134 USPQ 296, 299 (CCPA 1962). “[I]n some unpredictable areas of chemistry and biology, there is no conception until the invention has been reduced to practice.” MacMillan v. Moffett, 432 F.2d 1237, 1234-40, 167 USPQ 550, 552-553 (CCPA 1970). See also Hitzeman v. Rutter, 243 F.3d 1345, 58 USPQ2d 1161 (Fed. Cir. 2001) (conception simultaneous with reduction to practice where appellant lacked reasonable certainty that yeast’s performance of certain intracellular processes would result in the claimed antigen particles); Dunn v. Ragin, 50 USPQ 472, 475 (Bd. Pat. Inter. 1941) (a new variety of asexually reproduced plant is conceived and reduced to practice when it is grown and recognized as a new variety). Under these circumstances, conception is not complete if subsequent experimentation reveals factual uncertainty which “so undermines the specificity of the inventor’s idea that it is not yet a definite and permanent reflection of the complete invention as it will be used in practice.” Burroughs Wellcome Co. v. Barr Labs., Inc., 40 F.3d 1223, 1229, 32 USPQ2d 1915, 1920 (Fed. Cir. 1994).

Jump to MPEP SourcePlant Patent PracticeInventor of Discovered PlantPlant Patent Inventor and Oath
Topic

Continuing Application & Abandonment

1 rules
StatutoryInformativeAlways
[mpep-2138-04-206d28cb88f70f52397da615]
Abandoned Application Abandons Benefit of Filing as Constructive Reduction to Practice
Note:
An abandoned application, with no subsequent copending applications, forfeits the filing date as evidence of a complete invention and only proves conception.

An abandoned application with which no subsequent application was copending serves to abandon benefit of the application’s filing as a constructive reduction to practice and the abandoned application is evidence only of conception. In re Costello, 717 F.2d 1346, 1350, 219 USPQ 389, 392 (Fed. Cir. 1983).

Jump to MPEP SourceContinuing Application & AbandonmentAbandonment & Revival

Citations

Primary topicCitation
AIA Effective Dates
Key Changes Under AIA
35 U.S.C. § 100
AIA Effective Dates
Key Changes Under AIA
35 U.S.C. § 102
AIA Effective Dates
Key Changes Under AIA
35 U.S.C. § 102(g)
Process (Method)MPEP § 2106.04(b)
AIA Effective Dates
Key Changes Under AIA
MPEP § 2159
Inventor of Discovered Plant
Plant Patent Practice
Alpert v. Slatin, 305 F.2d 891, 894, 134 USPQ 296, 299 (CCPA 1962)
Testimony Request ProceduresBosies v. Benedict, 27 F.3d 539, 543, 30 USPQ2d 1862, 1865 (Fed. Cir. 1994)
Process (Method)Fiers v. Revel, 984 F.2d 1164, 1170, 25 USPQ2d 1601, 1605 (Fed. Cir. 1993)
PTAB Contested Case ProceduresGunter v. Stream, 573 F.2d 77, 197 USPQ 482 (CCPA 1978)
PTAB Contested Case ProceduresHitzeman v. Rutter, 243 F.3d 1345, 58 USPQ2d 1161 (Fed. Cir. 2001)
PTAB Contested Case ProceduresHybritech Inc. v. Monoclonal Antibodies Inc., 802 F. 2d 1367, 1376, 231 USPQ 81, 87 (Fed. Cir. 1986)
Continuing Application & AbandonmentIn re Costello, 717 F.2d 1346, 1350, 219 USPQ 389, 392 (Fed. Cir. 1983)
Invitrogen, Corp. v. Clontech Laboratories, Inc., 429 F.3d 1052, 1064, 77 USPQ2d 1161, 1169 (Fed. Cir. 2005)
Langer v. Kaufman, 465 F.2d 915, 918, 175 USPQ 172, 174 (CCPA 1972)
Process (Method)Oka v. Youssefyeh, 849 F.2d 581, 7 USPQ2d 1169 (Fed. Cir. 1988)
Process (Method)See also Amgen, Inc. v. Chugai Pharmaceutical Co., 927 F.2d 1200, 1206, 18 USPQ2d 1016, 1021 (Fed. Cir. 1991)
PTAB Contested Case ProceduresSee also Coleman v. Dines, 754 F.2d 353, 224 USPQ 857 (Fed. Cir. 1985)
Inventor of Discovered Plant
Plant Patent Practice
See also Hitzeman v. Rutter, 243 F.3d 1345, 58 USPQ2d 1161 (Fed. Cir. 2001)
Silvestri v. Grant, 496 F.2d 593, 596, 181 USPQ 706, 708 (CCPA 1974)
PTAB Contested Case ProceduresTownsend v. Smith, 36 F.2d 292, 295, 4 USPQ 269, 271 (CCPA 1929)

Source Text from USPTO’s MPEP

This is an exact copy of the MPEP from the USPTO. It is here for your reference to see the section in context.

BlueIron Last Updated: 2026-01-10